Michael Ward, who has died aged 80, was, as a young doctor, the medical linchpin of the successful 1953 ascent of Everest. As well as this, he organised the vital reconnaissance expedition in 1951 which explored the possibility of tackling Everest from the south, rather than the north, starting in Nepal, then a closed country.

Ward's discovery of a potential route to the summit from the south happened during his national service with the Royal Army Medical Corps when, rather romantically, he unearthed a dusty packet of aerial photographs taken by an RAF Mosquito fighter-bomber of this unexplored side of Everest.

Its climbable features were immediately apparent to Ward, who was an all-round mountaineer of considerable natural talent. Ward also came across a forgotten 1930s map, compiled from photographs and a photogrammatic survey. Convinced this was the key to the problem of climbing Everest from Nepal, he approached the Joint Himalayan committee of the Alpine Club and the Royal Geographical Society, faced down scepticism about a route into the Western Cwm through the perilous complexities of the Khumbu icefall, and persuaded committee members to approve the 1951 exploratory expedition. This project, led by Eric Shipton and which included Edmund Hillary, laid the groundwork for the latter's successful ascent two years later. It led to an invitation for Ward to join what was initially Shipton's, but which became (after some unpleasant politicking) John Hunt's expedition of 1953.

Ward's role as medical officer precluded much involvement in the climbing. With a group of fit and hardy mountaineers, there was little call on his professional expertise and he found the experience frustrating, though he did reach Camp 7 on the Lhotse Face.

Never a "yes man", Ward was outspoken about aspects of Hunt's leadership, particularly his self-inclusion in the final cadre of assault climbers: "He looked dreadful, but this was normal. I wondered how much longer he could go on flogging himself during the day ... Almost every time that I had seen him, over the last two weeks, he had looked the same and I had grave doubts about his ability to function efficiently high on the mountain even with oxygen."

James (later Jan) Morris, who covered the expedition for its sponsor, the Times, considered Ward the moving spirit of the enterprise and its most interesting member. He provided a deft, romantic portrait of Ward on treacherous ground at the head of the Khumbu icefall in the book Coronation Everest: "He was a slender, lithesome man, and it always gave me great pleasure, even in those disagreeable circumstances, to watch him in action. His balance was so sure, and his movements so subtle, that when he turned his grinning and swarthy face upon you it was as if someone had drawn in a moustache upon a masterpiece by Praxiteles."

Born in London, Ward was educated at Marlborough, where his housemaster was the 1930s Everester Edwin Kempson. His father, a civil servant in Malaya, was interned for six years by the Japanese, and after her escape his mother lived in a rented cottage in the Cotswolds.

Ward's mountaineering began at the age of 15, when he climbed the Wetterhorn. He went up to Peterhouse in 1943 to read natural sciences, came into contact at Cambridge with the charmed circle of Geoffrey and Len Winthrop Young, met Wilfrid Noyce and joined the university mountaineering club.

His talent as a rockclimber was apparent in the few days he spent in Snowdonia in 1947 with the great rockclimbing pioneer of the 1930s, Menlove Edwards, when they attempted the then-unclimbed White Slab on the finest of Welsh cliffs, Clogwyn Du'r Arddu.

They added a new and far more difficult direct finish to Jack Longland's climb of 1928 on the same cliff, and over on Glyder Fach repeated Edwards' imposing and gymnastic climb, Procrastination Cracks, with a far more difficult new start. Later that summer, while descending the Col de Coste-Rouge in the Ecrin massif, he and his companion, the Scottish climber Bill Murray, were hit by stonefall and fell a thousand feet, both of them suffering fractured skulls. The third man on the rope, John Barford, was killed.

After taking his natural sciences tripos, Ward continued his studies at the London hospital in Whitechapel. An idealistic doctor, he ardently espoused the newly inaugurated NHS, never practised privately, and spent his entire professional medical career until his retirement in 1993 at hospitals in the east end of London, as consultant surgeon for 30 years at St Andrew's, Bow, and later at Newham Hospital. Also, he lectured in surgery at London Hospital Medical College.

His physiological research into the effects of altitude was exemplary and influential, and his expeditions to the Greater Ranges [the world's highest and most challenging peaks] were many - including a reconnaissance in 1980 of Mount Kongur, an unclimbed 26,000ft giant in Sinkiang, China, which he led, and which was climbed by Chris Bonington's expedition, of which Ward was again a member, the following year.

Ward was a stylish writer, who compiled The Mountaineer's Companion (1966), an admired anthology of climbing writing, and published an excellent volume of mountain memoirs, In This Short Span (1972). In 1983 he was appointed CBE and awarded the Founder's Medal of the Royal Geographical Society for medical research, exploration and mountaineering in the Himalayas.

He remained active in the mountains. I remember climbing in Snowdonia with him when he was in his 70s, on a day of streaming summer rain. Ward's enthusiasm was undampened, and the company of this strong, saturnine and handsome man was a delight. He was by choice something of an outsider to a mountaineering establishment in this country which remains substantially in his debt.

Ward is survived by his wife Jane and by their son.

· Michael Phelps Ward, surgeon and mountaineer, born March 26 1925: died October 7 2005